Method and device for transmitting and receiving primary synchronization signal in wireless access system supporting narrowband internet of things

Abstract

The present invention provides a method and devices for transmitting and receiving a synchronization signal and a method for generating a synchronization signal in a wireless access system supporting narrowband Internet of Things (NB-IoT). A method for transmitting a primary synchronization signal (PSS) by a base station in a wireless access system supporting narrowband Internet of Things (NB-IoT), according to an embodiment of the present invention, can comprise the steps of: repeatedly generating first sequences n times so as to generate primary synchronization signals; multiplying n first sequences by second sequences and thus generating n primary synchronization signals; and transmitting n primary synchronization signals by means of n OFDM symbols, respectively. The size of a bandwidth used in the wireless access system supporting NB-IoT is the size of one physical resource block (PRB), and one PRB can comprise twelve subcarriers in a frequency domain.

What is claimed is: 
     
       1. A method performed by a User Equipment (UE) for receiving a primary synchronization signal (PSS) in a wireless access system supporting narrowband Internet of things (NB-IoT), the method comprising:
 receiving, by the UE from a base station, the PSS through a plurality of orthogonal frequency division multiplexing (OFDM) symbols; and 
 performing a cell search based on the PSS, 
 wherein the PSS is received based on applying elements of a cover code of length 11 to a Zadoff-Chu (ZC) sequence of length 11 with a root index equal to 5 in respective OFDM symbols of the plurality of OFDM symbols. 
 
     
     
       2. The method according to  claim 1 , wherein the plurality of OFDM symbols are assigned with “0” in resource elements, to which the PSS is not allocated. 
     
     
       3. The method according to  claim 1 , wherein the plurality of OFDM symbols are included in a subframe. 
     
     
       4. The method according to  claim 3 , wherein the plurality of OFDM symbols are OFDM symbols except for a control region in the subframe. 
     
     
       5. A User Equipment (UE) for receiving a primary synchronization signal (PSS) in a wireless access system supporting narrowband Internet of things (NB-IoT), the UE comprising:
 a transceiver; and 
 
       a processor operatively connected to the transceiver, 
       wherein the processor is configured to:
 control the receiver to receive, from a base station, the PSS through a plurality of orthogonal frequency division multiplexing (OFDM) symbols; and 
 perform a cell search based on the PSS, 
 wherein the PSS is received based on applying elements of a cover code of length 11 to a Zadoff-Chu (ZC) sequence of length 11 with a root index equal to 5 in respective OFDM symbols of the plurality of OFDM symbols. 
 
     
     
       6. The UE according to  claim 5 , wherein the plurality of OFDM symbols are assigned with “0” in resource elements, to which the PSS is not allocated. 
     
     
       7. The UE according to  claim 5 , wherein the plurality of OFDM symbols are included in a subframe. 
     
     
       8. The UE according to  claim 7 , wherein the plurality of OFDM symbols are OFDM symbols except for a control region in the subframe.